This is a review and detailed measurements of the Elac BS U5 "slim" 3-way coaxial speaker. It is on kind loan from a member. The U5 costs US US $856/pair everywhere so must have price control. I have read that it is designed for the European market with slimmer face and "modern" colors (black and white).
The feel, finish and looks are quite nice:
The coaxial driver above plays mid-range and woofer (or mid-woofer through mid-range and tweeter).
Nothing exciting on the back:
Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.
Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker can be used. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:
This is an unusual design. On-axis (black solid) is fairly even until about 3 kHz (where the tweeter takes over) but then we have a cycle of ups and downs. Speculating, they are diffraction interfering with the on-axis sound. Early window reflections that are at other angles, hardly show this problem (dashed blue top). There are directivity errors because of this so correction may not be easy with equalization.
We can look at the early window reflections in detail to confirm what I wrote above:
So no wonder that when we put everything together to predict the in-room response, all seems well:
Should sound good till we look at the distortion graphs with room effect filtered out:
Wow, this is quite a bit of distortion and occurring at crossover points. Is this a design problem with the coaxial driver?
We see the issue quite clearly in the context of overall frequency response:
I like to see nothing but blank space past 200 Hz and so yet we have many peaks here. Distortion is so high that I almost think it may be a measurement error but then I look at the review of Elac Adante AS-61 speaker and we have a similar issue:
That review did not use calibrated SPL levels but still, we clearly see the same rise in distortion at around 270 Hz. And another one before 2 kHz, both of which are near crossover frequencies.
This speaker makes a very good test case of whether distortion is an issue or not in absence of frequency response errors!
Our impedance and phase graph also shows a resonance point:
We kinda see the first resonance point in the CSD/waterfall as well:
You can see a trend around 300 Hz which dies down near 6 millisecond mark.
Coaxial driver brings with it good vertical directivity and we see some sign of it here:
Speaker Listening Tests
My first impression of tonality was good. Plenty of warmth due to bass response. Nice ability to play as loud as you want. But yet... the sound is not impressing me. Vocals, both female and male, sounded wrong for example.
I dial in some EQ for the elevated response above 1 kHz and that helps but still not there. I am out of normal tricks with EQ at this point as I usually have a clear guidebook of resonance peaks.
So I applying EQ to the clear distortion peaks. Reduction of level should reduce their levels as we see in the comparison graph of 86 and 96 dB above. I put those in together with my dip for my room mode:
This made a pretty good difference. Sound was more open, with more detail. I kept the Q high so that the impact on the frequency response is low (narrow notches).
At this point speakers became "good." They provide a diffused image which I like (especially since I am listening to a single channel in my reviews).
Conclusions
For a second time we see that the magic of coaxial drivers tends to be more for the eye than the ear. Distortion continues to be quite high and we have wavy output at highest frequencies. Perhaps there is no such thing as a cheap and good coaxial driver.
Or, I could be all wrong and they are fine.
I tend to be much more sensitive to distortion as party of my training so what bothered me, may not bother others.
Overall, I can't recommend the Elac BS U5. If you apply some equalization as I have, I could be pushed to recommend them for their high power handling and good tonality.
-----------
As always, questions, comments, recommendations, etc. are welcome.
This is the second review of the day. And on weekend no less. I demand overtime pay!!! Please donating what you can so I have something to show for it using : https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
The feel, finish and looks are quite nice:
The coaxial driver above plays mid-range and woofer (or mid-woofer through mid-range and tweeter).
Nothing exciting on the back:
Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.
Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker can be used. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:
This is an unusual design. On-axis (black solid) is fairly even until about 3 kHz (where the tweeter takes over) but then we have a cycle of ups and downs. Speculating, they are diffraction interfering with the on-axis sound. Early window reflections that are at other angles, hardly show this problem (dashed blue top). There are directivity errors because of this so correction may not be easy with equalization.
We can look at the early window reflections in detail to confirm what I wrote above:
So no wonder that when we put everything together to predict the in-room response, all seems well:
Should sound good till we look at the distortion graphs with room effect filtered out:
Wow, this is quite a bit of distortion and occurring at crossover points. Is this a design problem with the coaxial driver?
We see the issue quite clearly in the context of overall frequency response:
I like to see nothing but blank space past 200 Hz and so yet we have many peaks here. Distortion is so high that I almost think it may be a measurement error but then I look at the review of Elac Adante AS-61 speaker and we have a similar issue:
That review did not use calibrated SPL levels but still, we clearly see the same rise in distortion at around 270 Hz. And another one before 2 kHz, both of which are near crossover frequencies.
This speaker makes a very good test case of whether distortion is an issue or not in absence of frequency response errors!
Our impedance and phase graph also shows a resonance point:
We kinda see the first resonance point in the CSD/waterfall as well:
You can see a trend around 300 Hz which dies down near 6 millisecond mark.
Coaxial driver brings with it good vertical directivity and we see some sign of it here:
Speaker Listening Tests
My first impression of tonality was good. Plenty of warmth due to bass response. Nice ability to play as loud as you want. But yet... the sound is not impressing me. Vocals, both female and male, sounded wrong for example.
I dial in some EQ for the elevated response above 1 kHz and that helps but still not there. I am out of normal tricks with EQ at this point as I usually have a clear guidebook of resonance peaks.
So I applying EQ to the clear distortion peaks. Reduction of level should reduce their levels as we see in the comparison graph of 86 and 96 dB above. I put those in together with my dip for my room mode:
This made a pretty good difference. Sound was more open, with more detail. I kept the Q high so that the impact on the frequency response is low (narrow notches).
At this point speakers became "good." They provide a diffused image which I like (especially since I am listening to a single channel in my reviews).
Conclusions
For a second time we see that the magic of coaxial drivers tends to be more for the eye than the ear. Distortion continues to be quite high and we have wavy output at highest frequencies. Perhaps there is no such thing as a cheap and good coaxial driver.
Or, I could be all wrong and they are fine.
I tend to be much more sensitive to distortion as party of my training so what bothered me, may not bother others.Overall, I can't recommend the Elac BS U5. If you apply some equalization as I have, I could be pushed to recommend them for their high power handling and good tonality.
-----------
As always, questions, comments, recommendations, etc. are welcome.
This is the second review of the day. And on weekend no less. I demand overtime pay!!! Please donating what you can so I have something to show for it using : https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
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